The present invention relates to a pneumatic tire for a construction vehicle, which is used mainly in a construction site. More specifically, the present invention relates to a pneumatic tire for a construction vehicle, in which a reinforcement effect by a protector provided on a sidewall portion thereof is improved.
Since the pneumatic tire for a construction vehicle is used in a severe environment, for example, where the sidewall portion thereof is rubbed against obstacles such as rocks, a convex-shaped protector extended in a tire circumferential direction is provided on the sidewall portion thereof.
However, in the case where the protector is formed of the same rubber composition as that of the sidewall portion to be convex-shaped, a reinforcement effect thereof is not necessarily sufficient, and thus a situation occurs, where the sidewall portion suffers a cut damage while the tire is running, so that the tire becomes unusable before a wear lifetime thereof comes.
The object of the present invention is to provide a pneumatic tire for a construction vehicle, which is capable of enhancing the reinforcement effect by the protector provided on the sidewall portion.
In order to attain the foregoing object, a pneumatic tire for a construction vehicle according to the present invention comprises: at least two convex-shaped protectors extended in a tire circumferential direction, the protectors being provided in a range of 30 through 65% of a tire cross-sectional height on at least one of sidewall portions; and elastomeric reinforcing members buried inside the protectors, wherein a 100% modulus of the elastomeric reinforcing members is 5 through 25 times a 100% modulus of a rubber composition of the sidewall portion adjacent thereto.
As described above, since such high modulus elastomeric reinforcing members are buried inside the protectors, the reinforcement effect by the protectors can be enhanced, and the cut damage of the sidewall portions while the tire is running can be effectively prevented. Moreover, since the elastomeric reinforcing members have an appropriate modulus, even if the tire is used in a severe environment such as a construction site, the elastomeric reinforcing members hardly cause separation and exfoliation defects from the sidewall portions. It is preferable that the elastomeric reinforcing members have a fracture strength ranging from 10 through 50 MPa and a fracture elongation of 150% or more. As such elastomeric reinforcing members, an elastomeric reinforcing material is recommended for use, which is composed by crosslinking, with organic peroxides, a composition obtained by dispersing metal salt of acrylic acid or methacrylic acid into highly saturated rubber of ethylenic unsaturated nitrile-conjugate diene in which a content of conjugate diene units of 30% by weight or less.